.chat_foot{
    position: fixed;
    bottom: 0;
   display: flex; 
   height:44px;
   width: 100vw;
}

.msg_input{
    height:30px;
    flex-grow: 1;
}

.send_button{
    height:44px;
    line-height: 44px;
    font-size: 10px;
    width: 45px;
}

.chat_content{
    height: calc(100vh - 89px);
    overflow: auto;
}